Abstract: A method of making a plurality of optical record disc substrates includes the steps of injecting a resin material into a plurality of disc-shaped cavities which are formed by closing a fixed mold half and a movable mold half; and cooling the injected resin material in the cavities. The cavities are grouped into a plurality of groups so that each group includes not less than one cavity, and each group is provided with a common actuation device so that each actuation device is independently operated.

Abstract: Methods for manufacturing an optical disk having spiral or concentric grooves and land portions between the grooves are disclosed. In one aspect, the methods include projection of light spots onto a photosensitive material so that areas of the photosensitive material exposed to a first light spot form the pattern of spiral or concentric grooves and that areas of said photosensitive material which correspond to said land portions and are exposed to a second light spot form a predetermined pit pattern.

Abstract: An optical disk records digital information in optically-reflective layers that each vary in thickness between constructive interference of a monochromatic light and destructive interference of the said monochromatic light. The difference in the intensity of a reflected light beam subjected to interferometric constructive and destructive interference is used to communicate digital data from the optically-reflective layers and a detector. The optical disk provides for multiple layers of digital information that are tuned for interferometric response at correspondingly different monochromatic wavelengths of light. Another embodiment of the present invention is a mass-production process for making such an interferometric optical disk. Another embodiment of the present invention is a variation that includes layers that are emitting or absorbing depending on dopants.

Abstract: An arrangement is provided for a method of manufacturing optically readable discs in which a substrate is placed on a movable substrate carrier and by moving the substrate carrier it is subsequently placed in a centered position on a previously applied amount of replication material on a mold. In this position the substrate is fixed to the mold, after which the substrate carrier releases the substrate and the replication layer in the structure zone is solidified.

Abstract: In a mold for molding data discs having a stationary cylindrical member and a movable cylindrical member fixed to a stationary moldhalf and movable moldhalf respectively, in each of which a stationary mirror plate and a movable mirror plate are fixed, an outer peripheral ring is set on the outer peripheral surface of the movable mirror plate, having a protrusion in the lower portion of a small inner peripheral surface of the outer peripheral ring for preventing leakage of air blowing into a cavity to release the discs from the stamper.

Abstract: An improved method for forming a disc substrate having a bottomed centering hole for rotating and driving the disc. The method includes injecting synthetic resin into a mold cavity formed by a first and second metal molds to form the substrate, and punching at least part of the centering hole by a movable member protruded into the mold cavity to form a through-hole. A stamper containing digital information is held in place inside the mold cavity by its inner circumference by means of a vacuum or a magnet.

Abstract: A central aperture of a molded disc being severed by protruding of the gate cutter and also a molded disc being released from a cavity by blowing of air from the passage provided between an inner periphery of the central stamper holder and an outer periphery of the bushing into the cavity, the molten resin with which the protruded gate cutter is surrounded, is pressed by the first protrusion of an ejector sleeve for preventing occurrence of a round corner D formed along the edge of the central aperture and for preventing generating of the clouds on the surface of the information area of the disc.

Abstract: A system for defacing compact discs so as destroy information stored thereon includes a defacer unit and a feed unit for feeding discs one at a time, with vertical orientation, to the defacer unit. A falling vertically-oriented disc is caught and held between two sets of driven endless rubber belts which transport the disc between opposed knurling wheels which embed grooves in opposite sides of the disc substrate without, however, cracking the substrate. The knurling wheels are designed to give the grooves an identifiable pattern.

Abstract: A die assembly for molding a disc such as a compact disc, a video disc or the like by employing an injection molding process. The die assembly comprises a stationary die half including as essential components a stationary platen, a base die half, and an insert die half received on the stationary platen, and a movable die half. The insert die half includes a first insert for fixing the insert die half on the stationary platen, and a first mirror surface board removably received in a cavity of the first insert. The insert die half can be easily installed and removed into/from an installation space defined by a pair of retaining members and a die receiving member and when installed, it can be certainly and easily fixed by a pair of retaining members.

Abstract: An inventive method for producing an optical tape comprises the steps of sequentially depositing a label layer and a reflection layer on a substrate. The label layer and the reflection layer has a same reflexibility in a predetermined wavelength range of a laser beam, thereby providing a label image to a user as well as capability of information recording.

Abstract: An apparatus and method for producing an optical recording medium or an optical recording medium substrate sheet forms an photo-curable resin layer on at least one of a substrate sheet and a stamper which undergoes elastic deformation. The stamper bears a pattern corresponding with preformatting information and is brought into close contact with the substrate sheet wherein the photo-curable resin layer is interposed between them and cured.

Abstract: A process for manufacturing a substrate sheet for information recording mediums using a roll stamper including a flexible stamper member having a pattern corresponding to a preformat for an information recording medium, a first fixing member and a second fixing member integrally joined to both ends of the stamper member, and a pair of fit grooves capable of fittingly receiving the fixing members and formed in the periphery of a specular roll substrate in parallel to the axial direction of the specular roll substrate. The fixing members are fitted to the fit grooves so the stamper member is fixed along the periphery of the specular roll substrate between fit grooves. The first fixing member has a first member with a coefficient of linear expansion substantially equal to the coefficient of linear expansion of the stamper member and a second member having a larger coefficient of linear expansion than the coefficient of linear expansion of the first member.

Abstract: A method for preparing a substrate sheet for an optical recording medium has the steps of controlling a roll stamper having a preformat pattern on the peripheral surface thereof and a molding roll disposed with a predetermined gap between the same and the roll stamper so that they have a predetermined temperature, feeding a thermoplastic resin heated to a predetermined temperature to the gap from a means for extruding the thermoplastic resin disposed on the upstream side of the gap, while the roll stamper and the molding roll are rotated at a predetermined rotational frequency, and then molding the thermoplastic resin into a sheet by pressing the resin between the roll stamper and the molding roll to transfer the preformat pattern to the resin.

Abstract: A multilayered insulated mold structure for forming textured articles is disclosed. An insulation layer is deposited on the mold core and a multilayered skin layer is deposited on the insulation layer. The skin is formed of a plurality of sublayers, including a corrosion-resistant phosphorous-rich nickel region on the insulation layer acting as an etchant stop, and an non-corrosion resistant, or etchable, phosphorous-poor nickel region on the corrosion-resistant layer. The upper layer is uniformly textured by selective etching down to a depth terminating at the interface between the layers, but the insulation layer is protected. A method of molding uniformly textured articles is also disclosed, as is a method of making a mold suitable for producing uniformly textured articles and a method for making such a mold surface having bulk imperfections.

Abstract: A mold for molding a plurality of substrates for an information recording medium includes a fixing member, a plurality of units fixed to the fixing member, and a molding cavity. Each of the units has a preformat pattern with a surface corresponding to information recording medium formed on its surface, and the molding cavity is disposed opposite to the units so that the preformat patterns face the molding cavity.

Abstract: According to the present invention, etching is used to form a concave and convex pattern corresponding to information on an embossing metal mold comprising a conductive layer and a layer which includes an Ni electric-plating layer, or an Ni electric-plating layer, so that the surface of the embossing metal mold will not be contaminated even if processing conditions are somewhat changed, and that the mold will have less defects. Thus, optical disk substrates of high quality can be produced. Besides, time required for manufacturing a stamper can be shortened.

Abstract: A product, such as an optical disk substrate, having a minute surface pattern and a central hole is suitably obtained by an injection molding, wherein a resin is injected into a cavity defined by a mold including a movable half and a fixed half. The movable half is provided with an ejector ring reciprocally movable in a mold opening-and-closing direction and a gate cutter reciprocally movable at two strokes in the mold opening-and-closing direction. After the resin is injected into the cavity to form a product accompanied with a gate, the gate cutter is moved at a first stroke to cut the gate. Then the mold is opened, and substantially simultaneously with commencement of the mold opening, the product is released from the stamper and the gate cutter is moved at a second stage stroke in a direction causing the release of the product from the stamper.

Abstract: A process for producing an information recording medium comprising a substrate and provided thereon a recording layer and protective layer comprises the steps of forming on one substrate sheet a plurality of grooved preformats used for information recording mediums, forming a recording layer on the substrate sheet having thereon said plurality of grooved preformats, forming a protective layer on the substrate sheet on which said recording layer has been formed, and cutting the resulting substrate sheet into individual information recording mediums.

Abstract: A metal mold device for molding a substrate includes a fixed metal mold, a movable metal mold mounted facing the fixed metal mold for being moved towards and away from the fixed metal mold and for defining a mold cavity between it and the fixed metal mold, a stamper mounted on at least one of the fixed metal mold or the movable metal mold and arranged within the mold cavity, a positioning unit provided on the metal mold on which the stamper is mounted for positioning the loading position of the stamper, and a stamper supporting unit provided on the metal mold on which the stamper is mounted for supporting the stamper by suction. The stamper is positioned by the positioning member and held under suction by the stamper suction unit so that it may be mounted in position on the fixed metal mold or the movable metal mold to permit a disc substrate to be molded highly accurately.

Abstract: A roll stamper which molds a substrate resin sheet into an information recording media by continuously transferring preformat patterns on the substrate resin sheet, and a production process therefor. The preformat pattern on the roll stamper has a value of b/a of greater than 1 when the length of the preformat pattern in a direction parallel to the direction in which the resin sheet is transported is defined as a and the length in a direction perpendicular thereto as b.

Abstract: An apparatus and method for manufacturing a substrate sheet for information recording mediums having a roll stamper consisting of a flexible stamper having a pattern corresponding to a preformat for an information recording medium, the flexible stamper being fixed along the corresponding periphery of a roll substrate. A roll is placed opposite the roll stamper. A molten-resin sheet wider than the flexible stamper member is formed. The apparatus has means for bringing the edges of a resin sheet into contact with the roll substrate before releasing the resin sheet from the roll stamper. The temperature is controlled, so that a temperature difference on the surfaces of edges of a resin sheet and a preformat pattern transfer area of the resin sheet is kept within 30.degree. C. when the resin sheet is separated from the roll stamper after the molten-resin sheet has been pressed between the roll stamper and roll.

Abstract: A roll stamper for forming a substrate sheet for information recording mediums has a flexible stamper member having a pattern corresponding to a preformat for an information recording medium; a first fixing member and a second fixing member respectively joined to both ends of the stamper member in an integral form; and a pair of fit grooves capable of fittingly receiving the fixing members, formed in the periphery of a specular roll substrate in parallel to the axial direction of the specular roll substrate. The fixing members are so fitted to the fit grooves that the stamper member is fixed along the periphery of the specular roll substrate between the fit grooves.The first fixing member has a first member showing a coefficient of linear expansion substantially equal to the coefficient of linear expansion of the stamper member and a second member having a larger coefficient of linear expansion than the coefficient of linear expansion of the first member.

Abstract: A system for defacing compact discs so as destroy information stored thereon includes a defacer unit and a feed unit for feeding discs one at a time, with vertical orientation, to the defacer unit. A falling vertically-oriented disc is caught and held between two sets of driven endless rubber belts which transport the disc between opposed knurling wheels which embed grooves in opposite sides of the disc substrate without, however, cracking the substrate. The knurling wheels are designed to give the grooves an identifiable pattern.

Abstract: A roll stamper has a roll substrate and a stamper fixed thereto and having a convexity and concavity preformat pattern. The stamper has an auxiliary layer, including a material different from that of the stamper and a back surface on which the convexity and concavity preformat pattern is formed. The roll substrate has a low-melting layer on its surface and the auxiliary layer is in contact with the low-melting layer so that the stamper is fixed to the roll substrate.

Abstract: A roll stamper for forming an information recording medium substrate has a stamper member having a pattern corresponding to a pre-format for an information recording medium formed in its obverse surface, fixation members fixed to both end portions of a reverse surface of the stamper so as to be integral with the stamper member, and fit grooves formed in a circumferential surface of a specular roll base parallel to the axis of the specular roll base. The fixation members are fitted in the fit grooves, and the stamper member is fixed on the circumferential surface of the specular roll base. The roll stamper also includes a mechanism for applying a tensile force to the stamper member. This roll stamper is used in an apparatus having an extruder for melting and extruding a resin to form a resin sheet and a specular roll facing the roll stamper to continuously form the information recording medium substrate.

Abstract: In a mold for producing a disc having a stationary mold half and a movable mold half, an air passageway is provided in the stationary mold half to feed air into a cavity between the mold halves approximate the center of the disc being molded. Further, two air passageways are provided in the movable mold half to feed air into the cavity between the mold halves. One of the air passageways in the movable mold half feeds air into the cavity proximate the center of the molded disc while the second air passageway feeds air into the cavity proximate the outer periphery of the disc on the side toward the stationary disc. The air fed from the second air passageway of the movable mold half flows around the outer periphery of the disc and behind the disc to assist in separating the disc from the movable mold half.

Abstract: A method for forming a substrate sheet for optical recording media having a preformat on the surface is disclosed. This method has the steps of extruding a melted resin to form a melted resin sheet, pressing the melted resin sheet between a mirror roll and a resin roll prior to the curing of the melted resin sheet, thereby forming a resin sheet, the resin roll being disposed in the face of the mirror roll and being covered on the peripheral surface thereof with a resin, and forming a photocurable resin composition layer on the surface of the resin sheet with which the resin roll has come in contact, and forming the preformat on the photocurable resin composition layer.

Abstract: A process for producing a resin molding having a concave-convex pattern on the surface includes the steps of providing an original die having a concave-convex pattern on the surface and a substrate having a flat surface, thereby counterposing the concave-convex pattern surface and the flat surface to each other through a spacer and forming a cell with a cavity formed by the original die, the substrate and the spacer; making an internal pressure of the cell cavity lower than an external pressure thereof, thereby filling at least one of a liquid polymerizable component and a liquid resin into the cavity due to a pressure difference between the external pressure and the internal pressure; curing at least one of the polymerizable component and the liquid resin in the cavity, thereby making a replica; and peeling the original die from the replica, thereby obtaining a resin molding.

Abstract: A process for producing a roll stamper which molds a substrate sheet for information recording mediums by continuously transferring preformat patterns on a resin sheet. The roll stamper has the feature that the preformat pattern on the roll stamper has a value b/a of greater than 1, where the length of the preformat pattern in the direction parallel to the direction in which the resin sheet is transported is defined as a and the length in the direction perpendicular thereto as b.

Abstract: A substrate for an optical card having tracking grooves in a stripe form formed on the surface of an extrusion-molded thermoplastic resin sheet is characterized in that the direction of the tracking grooves is in parallel to the extrusion direction of the thermoplastic resin sheet, and the recording or reproduction using the optical card is characterized by that the optical card is bent and reciprocally moved along the direction of tracking grooves.

Abstract: In a method of manufacturing optically readable discs (1) a substrate (5) is placed on a movable substrate carrier (21) and by moving the substrate carrier it is subsequently placed in a centered position on a previously applied amount of replication material (11) on a mold (15). In this position the substrate is fixed to the mold, after which the substrate carrier releases the substrate and the replication layer in the structure zone (3) is solidified.

Abstract: A multi-cavity injection molding apparatus capable of simultaneously molding a plurality of optical disk substrates with a simple construction. The injection molding apparatus is constituted of a mold unit having a plurality of cavities and an injection unit for supplying a molten resin to the mold unit. The injection unit is provided with a plurality of nozzles for injecting the molten resin into the cavities, respectively.

Abstract: An optical disk having a pair of axially oppositely directed faces and an annular outer periphery is made by first forming a mold cavity corresponding to the shape of the disk between a pair of axially spaced parts and a demolding ring sandwiched between the parts. The cavity is then filled with a hardenable resin such that the parts form the respective faces and an inner periphery of the ring forms the outer periphery of the disk and the resin is at least partially hardened in the cavity. The parts are then axially oppositely separated from each other and from the disk to leave the disk in the ring with both of its faces exposed and the ring is then transversely displaced with the disk engaged in it out from between the mold parts. The disk is then cooled and shrunk such that its outer periphery separates from the inner periphery of the ring and the disk separates from the ring.

Abstract: A microstructure-bearing composite plastic article can be superior, both in microstructure and in physical properties, when it is a composite of a tough, flexible substrate, at a surface of which is microstructure formed of a cured oligomeric resin having hard segments and soft segments, which cured resin is substantially confined to the microstructure portion of the composite. Such a composite plastic article can be made by depositing an uncured oligomeric resin composition onto a master negative molding surface, filling the cavities by moving a bead of the composition between a substrate and the master, and curing the deposited composition by ultraviolet radiation while keeping the temperature during curing from rising not more than about 30.degree. C. above a typical use temperature of the finished composite plastic article.

Abstract: A metal mold for manufacturing a resin substrate useful as a optical recording medium.

Abstract: A method for preparing a substrate for an information recording medium, which comprises injecting a liquid resin into a mold for cast molding of a substrate for information recording medium having a plurality of units of mold for cast molding having an uneven preformat pattern on the surface arranged therein and solidifying the resin, and a mold for molding of the substrate.

Abstract: A roll-stamper for forming substrates of an information-recording medium includes at least one stamper being fastened along a peripheral face of a mirror roller, carrying on a surface thereof patterns each corresponding to a preformat for an information recording medium, also having stoppers fixed along both edges on the reverse side thereof, and being fastened to the mirror roller by inserting the stoppers respectively into negative stopping-grooves cut into the mirror roller in parallel with the axis of the mirror roller.

Abstract: A process for preparing a substrate sheet for optical recording mediums includes the steps of extruding a molten resin to form a resin sheet and bringing the resin sheet into pressure between a preformat roll and a roll disposed opposingly to said preformat roll to transfer a preformat pattern to the surface of the resin sheet, wherein the roll disposed opposingly to the preformat roll includes a roll whose surface is covered with an elastomeric resin.

Abstract: A process for producing an optical recording medium, including the steps of: melt-extruding a resin to form a resin sheet; passing the resin sheet under pressure between a first roller having a predetermined unevenness pattern and a second roller disposed opposite thereto before the resin sheet is hardened, thereby to transfer the unevenness pattern to a surface of the resin sheet; and forming a recording layer having an organic coloring matter on the surface of the resin sheet provided with the unevenness pattern; wherein the steps are conducted while the resin sheet is moved.

Abstract: A cast mold and process for casting a substrate for an information recording medium has an uneven preformat pattern formed on the mold surface. The uneven preformat features a pattern corresponding to tracking grooves and information pits, each information pit portion has a size with a length b in the direction parallel to the pattern of the tracking groove of 2 to 15 .mu.m and a width a in the direction perpendicular thereto of 1 to 6 .mu.m and a height c of 300 to 3500 .ANG.. The pit pattern has a pitch which is 1.8-fold or more of pit length b.

Abstract: An optical recording medium for an audio-video or ROM compact disc comprises a pitted translucent base material and a layer of a corrosion resistant metal or combination of metals from the group consisting of tantalum, chromium, cobalt, and nickel. For example, TaNi or CrCo can be applied to the surface, providing good adhesion, reflecting light, providing a printable surface, and not requiring any further coating such as a protective lacquer.

Abstract: A method and system for replicating microstructures surface relief patterns, such as diffraction patterns including holograms, by casting. A liquid casting resin is held between a surface relief master of the microstructure to be replicated and a substrate while the resin is hardened by actinic radiation curing. Application of resin to edges and discontinuities of the master is avoided in order to reduce undesirable build-up of resin on these areas of the master. The hardened resin surface relief replica may optionally be coated with a discontinuous graphical pattern of a clear or colored paint that eliminates the effect of the surface relief pattern in the regions so coated.

Abstract: A method of providing uniform thickness of a synthetic resin film upon molding of the synthetic resin film with a die having a plurality of heating elements arranged adjacent a die lip of the die. The thickness of a film molded by the die is measured by cutting a sample of the molded film in a direction perpendicular to the direction of drawing of the film, and measuring the thickness of the sample in the direction of cutting with a film thickness measuring device. The measured values are then fed to an arithmetic unit. At the arithmetic unit, a corresponding relationship is calculated, based on the measured film thickness values, between a one-sided material portion of the film and the plurality of heating elements, and amounts of heat to be generated by the corresponding heating elements are individually controlled in accordance with the relationship.

Abstract: An ultra-high-molecular-weight polyethylene sheet characterized in that it is formed into a sheet-like material of 100 to 300 .mu.m in thickness by extruding into a sheet form a feed polyethylene comprising an ultra-high-molecular-weight polyethylene having a viscosity-average molecular weight of 300,000 to 2,000,000.

Abstract: Improvement in a method for molding a plastic substrate for an optical disk having a concave-convex pattern on a side surface thereof including a step of feeding liquid resin into a molding cavity defined by a pair of mold halves, characterized in that, when the molded plastic substrate is released from the mold halves, the molded plastic substrate is released at least simultaneously in time from both of the mold halves in a mold-opening stage.

Abstract: An apparatus for producing a substrate sheet for optical recording media includes a device for continuously forming an ultraviolet-curable resin layer on at least one of i) a roll stamper having thereon a preformat pattern corresponding with preformatting information and ii) a substrate sheet; a means for bringing the substrate sheet into close contact with the roll stamper having the ultraviolet-curable resin layer; a device for curing said ultraviolet-curable resin layer to fix it on the substrate sheet; a device for peeling from the roll stamper the substrate sheet having the cured ultraviolet-curable resin layer; and a device for removing an ultraviolet-curable resin remaining on the surface of said roll stamper, provided after the means for peeling the substrate sheet.

Abstract: Electrolessly deposited metal holograms comprising a polymeric substrate having a holographic relief-patterned surface and a metal reflective layer electrolessly deposited to conform to and reproduce the holographic relief patterned. Light incident to the metal surface is reflected to provide an holographic reproduction of an holographic image inherent in said relief-patterned polymeric substrate.

Abstract: A process for producing an optical recording medium in a sheet form, including the steps of: melt-extruding a resin to form a resin sheet; and passing under pressure the resin sheet in a substantially melted state between a first heated roller having a predetermined unevenness pattern and a second heated roller disposed opposite thereto, thereby to transfer the unevenness pattern to a surface of the resin sheet.

Abstract: A process for producing a polycarbonate molded article having a low dust level from a polycarbonate resin in the form of a powder or pellets by injection molding using an injection molding machine. The injection molding machine includes a cylinder whose inner circumferential wall is made of a corrosion- and abrasion-resistant alloy from alloy components (1), (2), or (3) given below and a screw part made of a steel having a metal coating formed of hard chromium plating or hard nickel plating or formed of titanium carbide or tungsten carbide, or is made of SUS420, SUS440, Hastelloy C, or a steel of alloy component (4) given below:Alloy components (1):C: 0.5-1.5 wt%Si: 1.0-2.0 wt%B: 0.5-2.5 wt%Ni: 10.0-20.0 wt%Cr: 20.0-30.0 wt%W: 10.0-20.0 wt%Cu: 0.5-2.0 wt%Remainder: Co and unavoidable impurities,Alloy components (2):Ni: 0.0-2.0 wt%Cr: 5.0-15.0 wt%Fe: 0.0-1.0 wt%Mn: 0.1-2.0 wt%Si: 0.2-4.0 wt%B: 2.0-4.0 wt%Remainder: Co and unavoidable impurities,Alloy components (3):Cr: 5.0-10.0 wt%Co: 5.0-40.0 wt%Fe: 0.0-10.

Abstract: Stretched surface recording disk (SD) 10 comprises an annular support 12 having raised annular ridges 42 and 28 at its inside and outside diameters 22 and 30 with a base portion 24 in between the two ridges, and an annular recording medium film 14 held in radial tension and stretched across the base portion by adhering the film to attachment surfaces 48 and 36 near the inside and outside diameters respectively. The SD is annealed twice during manufacture to relieve stress in the stretched film 14. This annealing results in SD essentially free from track anisotropy and stress distribution anisotropy in the plane of the disk. As a result, data tracks are more stable than in previous SD, track density can be greater, and the SD is generally more reliable.